Chromatography has found wide spread use in the analytical separation of components in liquid or gas mixtures. The term chromatography is generally applied to all multiple partitioning of mixtures that lead to individual zones of migration for components of the mixture. Chromatography involves a mobile phase and a stationary phase. The molecules of the mixture migrate along the stationary phase at a rate proportional to their relative affinities for the mobile and stationary phases. The volume of mobile phase required for separation is usually orders of magnitude greater than the volume of solute molecules separated. Because of this a second separation is usually required to recover the desired molecules from the mobile phase. This drawback has generally limited the applicability of chromatography to small-scale separations.
It is known to use counter current chromatography as a method for separating liquids by utilizing the hydrodynamic behavior of the two immiscible solvents in a rotating coiled tube. It is further known to use a centrifugal type liquid chromatography whereby centrifugal force is used to push a mobile phase across a spinning disk coated with a stationary phase. It is also known to use electrostatic charge in the separation of solids.